Animal setae

Setae in annelids
are stiff bristles present on the body. They help for example
earthworms to attach
to the surface and prevent backsliding during peristaltic motion. These
hairs are what make it difficult to pull a worm straight from the
ground. Setae in polychaetes (a group
including earthworms) are largely composed of chitin.

Setae on gecko
footpads are small hair-like processes
responsible for the animal's ability to cling to vertical
surfaces.

Plant setae

In botany, "seta" refers to the
stalk supporting the capsule of a moss, hornwort or liverwort, and supplying it
with nutrients. The seta has a short foot embedded in the gametophyte from which it
grows. Setae are not present in all mosses, but in some species they may reach 15 to 20
centimeters in height.

Artificial setae

The development of adhesives that detach
at will yet display substantial stickiness is of great importance
for various technological fields.